Thyrotoxic periodic paralysis with ventricular tachycardia.

Area of Science:

• Endocrinology
• Neurology
• Cardiology

Background:

• Thyrotoxic periodic paralysis (TPP) is an episodic neuromuscular disorder characterized by acute, severe muscle weakness.
• It is predominantly seen in young men of Asian descent and is associated with hyperthyroidism.

Observation:

• A 47-year-old male presented with acute limb weakness following sleep.
• Physical examination revealed significant muscle weakness (upper limbs 3/5, lower limbs 2/5).
• ECG showed wide QRS complex, monomorphic ventricular tachycardia, ST depression, and a long QT interval, alongside extremely low serum potassium (1.0 mEq/L).

Findings:

• The patient was diagnosed with hyperthyroidism, indicated by low TSH (<0.03 micro-IU/mL) and high free T4 (2.43 ng/dL).
• Treatment with methimazole led to normalization of potassium levels (5.1 mEq/L) and resolution of symptoms.
• The final diagnosis was thyrotoxic periodic paralysis (TPP).

Implications:

• This case highlights the critical association between hyperthyroidism and hypokalemic periodic paralysis.
• Early recognition of TPP is vital for preventing life-threatening cardiac arrhythmias and neurological complications.
• Management involves treating the underlying hyperthyroidism and correcting electrolyte imbalances.